A number of renewable energy sources exist that are adapted to use forces of nature to generate power. Examples of such sources include, but are not limited to offshore wind, ocean currents, and ocean waves. These sources, however, are intermittent and/or time-variable in nature. Since their productive time intervals are not generally correlated with the time intervals of load demand, these renewables are not well accepted by the power industry.
In order to be more useful, such intermittent, but otherwise sustainable power sources must be integrated with large, readily accessible means of systemic energy storage and subsequent power production. Existing, accepted energy storage means are generally terrestrial (pumped storage), that are not readily available to offshore renewable energy sources. Those that are, such as batteries, are excessively heavy, short lived and expensive, and may be dangerous to the environment.